Check valve flap for fluid injector

ABSTRACT

A backflow-prevention system that substantially prevents contaminant backflow at a treatment site. The system includes a fluid ejector tube for insertion into the patient&#39;s mouth and a backflow prevention device that receives fluid from the fluid ejector tube. The backflow prevention device includes an internally positioned valve member. The valve member limits contaminant backflow. The valve member is movable between open and closed positions based on a vacuum pressure condition in the system.

This application claims priority to and is a Continuation-In-Part of PCTUS08/64302 filed on May 21, 2008 and titled IMPROVED CHECK VALVE FORFLUID INJECTOR, and is a Continuation-In-Part of U.S. patent applicationSer. No. 11/751,803, filed on May 22, 2007 and titled IMPROVED CHECKVALVE FOR FLUID INJECTOR, the entire disclosures of which areincorporated by reference.

TECHNICAL FIELD

The present disclosure generally relates to suctioning devices, and moreparticularly to medical and dental suctioning devices that are adaptedto inhibit backflow of suctioned materials in the suctioning device.

BACKGROUND

Cross-contamination between patients, for example, dental patients, canoccur when suctioning devices attached to vacuum lines are used toremove various bodily and/or externally introduced fluids. Although thedisposable distal ends of these devices typically are changed betweenpatients, the vacuum lines employed typically are not changed. Saliva,blood and other contaminants pass from the distal end into the vacuumline, where they can remain until arrival of the next patient. When anew distal end is inserted onto the vacuum line for a new patient,contaminants from the previous patient can backflow from the vacuum lineinto the distal end and enter the patient's mouth, for example. Clearly,with the growing incidence of AIDS and other communicable diseases, thisis a situation to be avoided.

A number of prior art devices have attempted to prevent backflow and theresulting likelihood of cross-contamination between patients. U.S. Pat.Nos. 5,425,637 and 5,509,802 to Whitehouse, et al. and 5,464,397 toPowers, Jr., which are incorporated herein by reference, disclose priorart attempts to prevent or at least minimize contaminant backflow andcross-contamination. The two Whitehouse patents disclose suction lineshaving vacuum-release apertures through a tubular sidewall of a salivaejector tip. If a patient closes his or her lips around the tip, thevacuum-release aperture is said to prevent creation of a temporary highvacuum in the patient's mouth; the aperture also likely preventsstoppage of air and/or fluid, at least between the aperture and the restof the system. The Powers, Jr. patent, on the other hand, appears torely merely on a “tortuous path” within the device to substantiallyprevent backflow of bacteria.

However, as recent studies are believed to have shown, a boundary layercan form around the internal circumference of many currently usedsuctioning devices. The boundary layer is the portion of air and/orother fluid flowing in the immediate vicinity of the internalcircumference. Flow within the boundary layer is severely reduced, eveneliminated due to the forces of adhesion and viscosity caused by theinternal circumference. Because suction within the boundary layer isreduced or eliminated, a “bio-film” can be created, allowing saliva,blood and other contaminants to flow by gravity, for example, from themain vacuum system of a dental office, through saliva ejector assembliesand into the mouths of patients.

It is believed that prior art suctioning devices do not adequatelyaccount for or address backflow caused by boundary layer conditions,and/or other conditions such as mouth-induced backflow suction. Priorart devices thus allow an unacceptably high likelihood ofcross-contamination between patients. Clearly, a need has arisen for asolution to this problem.

SUMMARY

One aspect of the present disclosure relates to a backflow preventionsystem that can substantially prevent contaminant backflow from a vacuumdevice into a patient's mouth. The system in accordance with the presentdisclosure includes a fluid ejector tube for insertion into thepatient's mouth and for removal of saliva, blood, etc. when a vacuumpressure is applied. A backflow prevention device receives fluid fromthe fluid ejector tube. Valve componentry disposed within the backflowprevention device includes a housing and a valve flap operably supportedby the housing to engage the valve seat and prevent contaminant backflowupon release of the vacuum. Upon application of a vacuum condition, thevalve flap moves to an open orientation to permit fluid flow away fromthe patient's mouth. The valve flap can include stiffening features thatprovide increased resistance to bending of the valve flap (i.e.,increased rigidity or reduced flexibility) to help maintain the valveflap in a closed orientation until a threshold vacuum pressure conditionexists. The stiffening features can be in the form of additional layersof material in the valve flap. The stiffening features can also includestiffening structures that extend from a surface of the valve flap orare embedded within the valve flap. Corresponding devices and methodsprovide similar advantages.

Another aspect of the present disclosure relates to valve flapconfigurations generally. The valve flap can include features thatinfluence bending characteristics of the valve flap. For example, thevalve flap can include recesses, protrusions, additional layers ofmaterial, and embedded material that can increases a resistance tobending in at least portions of the valve flap.

Another aspect of the present disclosure relates to a backflowprevention device that includes a distal housing portion, a proximalhousing portion, and a valve member. The valve member is movable in thehousing between open and closed orientations upon application of avacuum pressure condition in the housing. At least one of the distal andproximal housing portions can include a protrusion that engages thevalve flap to bias the valve flap into a particular orientation. Atleast one of the distal and proximal housing portions can include arecess feature sized to receive at least a portion of a stiffeningstructure of the valve flap. At least one of the distal and proximalhousing portions can include at least one vent opening along a lengththereof that bypasses the valve flap.

The above summary is not intended to describe each disclosed embodimentor every implementation of the inventive aspects disclosed herein.Figures in the detailed description that follow more particularlydescribe features that are examples of how certain inventive aspects maybe practiced. While certain embodiments are illustrated and described,it will be appreciated that disclosure is not limited to suchembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of an example suction system inaccordance with the present disclosure.

FIG. 2 is a schematic side view of the example suction system shown inFIG. 1 with the cover member positioned on the ejector tube.

FIG. 3 is schematic exploded side view of the example suction systemshown in FIG. 1.

FIG. 4 is a schematic cross-sectional side view of the example suctionsystem shown in FIG. 1.

FIG. 5 is a schematic side view of an example assembly in accordancewith the present disclosure that includes an ejector tube, backflowdevice and cover, wherein the cover includes a sealed end near theejector tip.

FIG. 6 is a schematic side view of the example assembly shown in FIG. 5,wherein the cover includes a sealed end near the backflow device.

FIG. 7 is a schematic side view of another example assembly inaccordance with the present disclosure that includes an ejector tube andcover.

FIGS. 8A-D are schematic cross-sectional side views showing examplecover members in accordance with the present disclosure.

FIG. 9 is a schematic perspective view showing continuous length covermember in a rolled up state.

FIG. 10 is a schematic cross-sectional side view of an example backflowdevice in accordance with the present disclosure, wherein the valve flapis in a closed state.

FIG. 11 is a schematic cross-sectional side view of the example backflowdevice shown in FIG. 10, wherein the valve flap is in an open state.

FIG. 12 is a schematic cross-sectional side view of the proximal housingportion of the backflow device shown in FIG. 10.

FIG. 13 is a schematic end view of the proximal housing portion shown inFIG. 12.

FIG. 14 is a schematic cross-sectional side view of the distal housingportion of the backflow device shown in FIG. 10.

FIG. 15 is a schematic end view of the distal housing portion shown inFIG. 12.

FIGS. 16A-F are schematic front views of several example valve flaps foruse with the backflow devices shown herein.

FIGS. 17A-F are schematic bottom views of the example valve flaps shownin FIGS. 16A-E.

FIGS. 18A-F are schematic cross-sectional side views of the valve flapsshown in FIGS. 16A-E.

FIG. 19A is a schematic cross-sectional side view of another examplebackflow device in accordance with the present disclosure, wherein thevalve flap is in a closed state.

FIG. 19B is a schematic exploded cross-sectional side view of thebackflow device shown in FIG. 19A.

FIG. 19C is a schematic cross-sectional side view of the examplebackflow device shown in FIG. 19A, wherein the valve flap is in an openstate.

FIG. 19D is a schematic exploded cross-sectional side view of thebackflow device shown in FIG. 19C.

FIG. 20A is a schematic cross-sectional side view of another examplebackflow device in accordance with the present disclosure, wherein theconnection protrusion includes a barb construction.

FIG. 20B is a schematic exploded cross-sectional side view of thebackflow device shown in FIG. 20A.

FIG. 20C is a schematic exploded cross-sectional side view of thebackflow device shown in FIG. 20A and further including a rib andchannel connection arrangement on the proximal and distal housingportions.

FIG. 20D is a schematic perspective view of the distal housing portionof the backflow device shown in FIG. 20C.

FIG. 20E is a schematic perspective view of the proximal housing portionof the backflow device shown in FIG. 20C.

FIG. 21A is a schematic cross-sectional side view of another examplebackflow device in accordance with the present disclosure, wherein thevalve flap is in a closed state.

FIG. 21B is a schematic exploded cross-sectional side view of thebackflow device shown in FIG. 21A.

FIG. 22 is a schematic front view of another example valve flap inaccordance with the present disclosure, wherein the valve flap isbendable about a lateral centerline.

FIG. 23 is a schematic cross-sectional side view showing fluid flowthrough another example backflow device that includes the valve flap ofFIG. 23.

FIG. 24A is a schematic cross-sectional side view of another examplebackflow device in accordance with the present disclosure, wherein thebiasing protrusion includes a connection protrusion.

FIG. 24B is a schematic exploded cross-sectional side view the examplebackflow device shown in FIG. 24B.

FIG. 24C is a schematic cross-sectional side view of another examplebackflow device in accordance with the present disclosure, whereinbiasing protrusion and retention protrusion are shaped to bias the valveflap in a closed state.

FIG. 24D is a schematic exploded cross-sectional side view of theexample backflow device shown in FIG. 24D.

FIG. 25 is a schematic cross-section side view of an example assembly inaccordance with the present disclosure, wherein the assembly includes anejector tube and an ON/OFF valve boot, the boot including a backflowvalve member.

FIG. 25A is a schematic exploded cross-sectional side view of theassembly shown in FIG. 25.

FIG. 26 is a schematic cross-section side view of another exampleassembly in accordance with the present disclosure, wherein the assemblyincludes an ejector tube and an ON/OFF valve boot, the boot including abackflow valve member.

FIG. 26A is a schematic exploded cross-sectional view of the assemblyshown in FIG. 26.

FIGS. 27A-D are schematic cross-sectional side views of several exampleON/OFF valve boots having a backflow valve member in accordance with thepresent disclosure.

FIGS. 28A-D are schematic cross-sectional end views of the ON/OFF valveboots shown in FIGS. 27A-D.

FIG. 29 is a schematic side view of another example assembly inaccordance with the present disclosure, wherein the assembly includes anON/OFF valve, an ejector tube, and a cover member.

FIG. 30 is a schematic side view of another example assembly inaccordance with the present disclosure, wherein the assembly includes anON/OFF valve, an ejector tube, and a cover member, the cover memberbeing drawn from a continuous cover member that is housed proximal ofthe ON/OFF valve.

FIG. 31 is a schematic side view of the cover member and housing shownin FIG. 30.

FIG. 32 is a schematic cross-sectional side view of the side member andhousing shown in FIG. 31, wherein the cover member is completelyretained in the housing.

FIG. 33 is a schematic cross-sectional side view of another example sidemember housing in accordance with the present disclosure, the sidemember housing including a fastener member to hold a position of theside member housing member relative to the ON/OFF valve.

FIG. 34 is a schematic exploded cross-sectional side view of anotherexample backflow device in accordance with the present disclosure,wherein the valve flap is retained by a pair of oppositely arrangedbarbs.

FIG. 35 is a schematic perspective view of a distal housing portion ofthe backflow device shown in FIG. 34.

FIG. 36 is a schematic perspective view of a proximal housing portion ofthe backflow device shown in FIG. 34.

FIG. 37 is a schematic exploded cross-sectional side view of anotherexample backflow device in accordance with the present disclosure,wherein the distal and proximal housing portions define an arch shapedvalve seat.

FIG. 38 is a schematic perspective view of a housing portion of anotherexample backflow device, wherein the housing portion defines an airinlet port.

FIG. 39 is a schematic cross-sectional side view of a housing portion ofanother example backflow device, wherein the housing portion defines aplurality of air inlet ports.

FIG. 40 is a schematic cross-sectional side view of a housing portion ofanother example backflow device, wherein the housing portion includes aplurality of external contact rib members.

FIG. 41 is a schematic end view of the housing portion shown in FIG. 40.

FIG. 42 is a schematic exploded cross-sectional side view of anotherexample backflow device in accordance with the present disclosure,wherein the features of the housing portions assist in orienting thevalve flap relative to the housing portions.

FIG. 43 is a schematic cross-sectional side view of the backflow deviceshown in FIG. 42.

FIGS. 44-53 are schematic cross-sectional side views of several examplevalve flap configurations in accordance with principles of the presentdisclosure.

FIG. 54 is a schematic front view of another example valve flapconfiguration having a plurality of round stiffening members.

FIGS. 55-56 are schematic cross-sectional side views of the valve flapshown in FIG. 54.

FIG. 57 is a schematic front view of another example valve flapconfiguration having a plurality of liner intersecting stiffeningmembers.

FIGS. 58-59 are schematic cross-sectional side views of the valve flapshown in FIG. 57.

FIG. 60 is a schematic front view of another example valve flapconfiguration having a plurality of concentric stiffening members, oneof which is a partial circumferential construction.

FIGS. 61-62 are schematic cross-sectional side views of the valve flapshown in FIG. 60.

FIG. 63 is a schematic front view of another example valve flapconfiguration having a plurality of concentric stiffening members.

FIGS. 64-65 are schematic cross-sectional side views of the valve flapshown in FIG. 63.

FIG. 66 is a schematic front view of another example valve flapconfiguration having a plurality of parallel stiffening members.

FIGS. 67-68 are schematic cross-sectional side views of the valve flapshown in FIG. 66.

FIGS. 69-71 and 74 are schematic cross-sectional side views of severalexample backflow prevention assemblies in accordance with principles ofthe present disclosure.

FIGS. 72-73 are schematic perspective view of the proximal and distalhousing portions shown in FIG. 71.

FIGS. 75-77 are schematic cross-sectional side views of portions offurther example proximal housing portion constructions in accordancewith principles of the present disclosure.

FIG. 78 is a schematic cross-sectional side view of another example setof proximal and distal housing portion in accordance with principles ofthe present disclosure.

FIG. 79 is a schematic cross-sectional side view of a portion of thedistal housing member shown in FIG. 78 and a portion of a valve flap.

DETAILED DESCRIPTION

Various embodiments will be described in detail with reference to thedrawings, wherein like reference numerals represent like parts andassemblies throughout the several views. Reference to variousembodiments does not limit the scope of the claims attached hereto.Additionally, any examples set forth in this specification are notintended to be limiting and merely set forth some of the many possibleembodiments for the appended claims.

The following discussion is intended to provide a brief, generaldescription of a suitable environment in which the invention may beimplemented. Although not required, the invention will be described inthe general context of vacuum suction devices, for example, a dentalsaliva ejector device. The structure, creation, and use of some exampledental fluid ejector devices are described hereinafter.

The example embodiments disclosed herein have wide application to anumber of medical procedures and environments. Suction is often used indental applications, as described above. Suctioning devices are alsotypically used to drain fluid and remove blood from many surgicalenvironments, aid in respiration, and aid in a number of other medicaland surgical procedures. Additionally, suctioning devices in whichcross-contamination is undesirable are used in non-medical andnon-surgical environments, such as in some types of liquid soapdispensers where preventing backflow of a fluid is required. Therefore,while most of the embodiments described with reference to the attachedfigures are directed to dental devices and applications, many otherapplications and related embodiments are envisioned.

The Example Suction Assemblies of FIGS. 1-24D

Several example suction assemblies 10 are described now with referenceto FIGS. 1-24D. The suction assembly 10 includes an ejector tubeassembly 12, a backflow prevention assembly 14, an ON/OFF valve assembly16, a vacuum hose 18, and a cover member 20. These features are shown inthe exploded view of FIG. 3 and in further detail in the cross-sectionalview of FIG. 4. The features 12, 14, 16, 18, 20 can be combined asseparate subassemblies that are coupled together at the point of usewhere, for example, a patient is being treated by the suction assembly10. In one example, the ejector tube assembly 12 and cover member 20 arearranged as a subassembly that is later connected to the backflowprevention assembly 14, or in alternative embodiments connected directlyto the ON/OFF valve assembly 16. In another example arrangement, theejector tube assembly 12, backflow prevention assembly 14, and covermember 20 are provided as a subassembly that is removably engaged withthe ON/OFF valve assembly 16. Other subassembly arrangements arepossible, some of which are described in further detail below.

The ejector tube assembly 12 includes an ejector tube 22, having distaland proximal ends 24, 26, an outer diameter D1, a length L1, and anejector tip 28 (see FIG. 3). The ejector tube 22 can be referenced as,for example, a fluid or liquid ejector tube, a saliva ejector tube, aparticle ejector tube, or a fluid source tube. The ejector tube 22 canhave a contoured shape. The contoured shape of the ejector tube 22 canbe preformed. In some arrangements, the ejector tube assembly 12 caninclude a stiffening member such as a wire that extends along at least aportion of the length of the tube 22 that provides adjustability of thecontoured shape and retention of that shape due to the inherentstiffness of the stiffening member. The outer diameter D1 is typicallysized to provide insertion of the proximal end 26 into the distal end ofthe backflow prevention assembly 14. The ejector tip 28 can have variousconstructions that provide proper fluid flow into the ejector tubeassembly 12.

The backflow prevention assembly 14 includes a proximal housing portion30, a distal housing portion 32, and a valve flap 34. Other examplebackflow prevention assemblies are disclosed in co-owned U.S. Pat. No.6,203,321, which is incorporated herein by reference. Many of theembodiments disclosed in U.S. Pat. No. 6,203,321 require a plurality ofcomponents used in the valving structure within the backflow preventionassembly. Further, many of the examples disclosed in U.S. Pat. No.6,203,321 include valving components that are molded, which can increasethe complexity and cost associated with generating those valvingcomponents.

Referring now to FIGS. 10-21B, the proximal housing portion 30 includesa neck portion 36, a biasing protrusion 38, a first mating surface 40, apair of connection recesses 42, a second mating surface 44, and a floworifice 46. The proximal housing portion 30 can also include a pluralityof barbed members (e.g., barbs 48 that are shown positioned interior ofthe distal housing portion 32) that can be positioned on an exterior ofthe neck portion 36 to help retain the backflow prevention assembly 14in engagement with the ON/OFF valve assembly 16.

The biasing protrusion 38 is positioned vertically above the connectionrecesses 42. A distal end of the biasing protrusion 38 extends distallyin the axial direction beyond the first mating surface 40 (see FIG. 12).The biasing protrusion 38 exerts an axially directed force upon thevalve flap 34 when the backflow prevention assembly 14 is assembled.

The distal housing portion 32 includes a pair of connection protrusions50, a tube orifice 52, a mating member 54, and a valve seat 56 (see FIG.14). The connection protrusions 50 are sized to extend through the valveflap 34 and into the connection recesses 42 by the proximal housingportion. The tube orifice 52 is sized to receive the proximal end of theejector tube 22. The distal housing portion 32 can further include aplurality of barbs 48 that are positioned along the tube orifice surface52. The barbs 48 are configured to engage an outer surface of theejector tube 22 to provide an improved connection between the ejectortube assembly 12 and backflow prevention assembly 14. The mating member54 is sized to engage the first and second mating surfaces 40, 44 of theproximal housing portion 30. The outer diameter surface of the matingmember 54 can engage the second mating surface 44 with an interferencefit that promotes retention of the proximal and distal housing portionstogether.

In some arrangements, a connector, fastener, adhesive, or otherconnecting means can be used to secure the proximal and distal housingportions 30, 32 together in a permanent connection or in a connectionarrangement in which the proximal and distal housing portionsreleaseably engaged with each other. In one example, a latchingarrangement can be used on the mating surfaces 40, 44 to provide asnap-fit connection between the housing portions 30, 32. An examplearrangement includes a pair of protrusions (not shown) are positioned onthe surface 40 at 180° spaced apart locations. The protrusions areconfigured to engage within a pair of recesses (not shown) positioned onthe surface 44 also at 180° spaced apart locations, wherein engagementof the protrusions (not shown) in the recesses (not shown) provide asnap-fit connection between the housing portions 30, 32. The snap-fitconnection can be permanent, in that the connection cannot bedisconnected without permanent damage to the housing portions 30, 32, orreleasable in construction to permit disconnecting of the housingportions 30, 32 without permanent damage being caused.

The use of a single protrusion/recess pair or at least threeprotrusion/recess pairs can be used to provide a desired connectionbetween the housing portions 30, 32. The protrusion/recess pair can haveany configuration and structure that limits relative axial movement ofthe housing portions 30, 32 after the connection between the protrusionand recess are made.

Further, a snap-fit connection such as the protrusion/recessconfiguration described above, can be used in combination with otherconnecting and/or aligning features. Referring to FIGS. 20C-E, anexample rib 1 and channel 2 arrangement is shown. The rib 1 ispositioned on the proximal housing portion 30 and the channel 2 ispositioned on the distal housing portion 32. The rib 1 and channel 2 arearranged in an axial direction. The channel 2 is exposed on a proximalend 3 of the distal housing portion 32. The channel 2 and rib 1 can bepositioned at any radial location around the circumference of thehousing portions 30, 32. The channel 2 and rib 1 can be exchanged to beon the opposite housing portion 30, 32.

More than one pair of channel/rib features can be included on any givenpair of housing portions 30, 32. For example, a pair of channel/ribfeatures can be included for each protrusion/recess pair included on apair of housing portions 30, 32. In one example, a pair of channel/ribfeatures can be positioned radially adjacent to a protrusion/recess pairon the housing portions 30, 32. The channel 2 and rib 1 can be sized toprovide an interference fit there between when engaged with each other.Engagement of the channel 2 and rib 1 can reduce axial, radial, androtational movement of the housing portions 30, 32 when the housingportions 30, 32 are connected together with the valve flap 34 capturedthere between.

Other alignment features besides a pair of channel/rib features can beused to help align the housing portions 30, 32 relative to each otherwhen connecting the housing portions 30, 32 together.

The valve flap 34 includes a pair of connection apertures 60, a top endportion 62, a bottom end portion 64, and a diameter D2. The valve flap34 is sized with a thickness that permits the connection protrusions 50to extend through the connection aperture 60 and into the connectionrecesses 42 with the valve flap 34 positioned between the first matingsurface 40 of the proximal housing portion 30 and the valve seat 56 ofthe distal housing portion 32. The diameter D2 of the valve flap 34 issized no greater than the maximum internal diameter of the valve seat56.

In other arrangements, the connection protrusions 50 do not extendcompletely through the connection recesses 42. The connectionprotrusions 50 can be configured to extend only partially through thethickness of valve flap 34. In other arrangements, the valve flap 34does not include connection apertures and the connection protrusions 50are configured to apply a compression force against the valve flap 34 tohelp retain the valve flap in place. The connection protrusions 50 canhave a construction that promotes either concentrated point contact(i.e., a “pinching” contact) with the valve flap 34 or self-penetrationof the valve flap 34. FIGS. 20A-C and 24B-C illustrate barb-shapedconnection protrusions 50, 250 that engage a valve flap 34, 234 (e.g.,see example valve flap 34 shown in FIG. 16F that does not includeconnection recesses 42). The connection protrusions 50, 250 of FIGS.20A-C and 24B-C can also be used with a valve flap 34 having connectionrecesses 42 aligned with the connection protrusions 50, 250. One exampleconnection recess 42 (not shown) for use with connection protrusions 50,250 shown in FIGS. 20A-C and 24B-C has a shape and size thatsubstantially matches the barb shape of the connection protrusion 50. Instill further arrangements, different numbers of connection protrusionsand connection recesses can be used to help retain the valve flap. Forexample, any number from 0 to 3 or more connection protrusions andconnection recesses can be used. The connection protrusions 50 can bealso be referenced as valve retention members or pins.

The valve flap 34 can have many different configurations (e.g., size andshape) for use with the example proximal and distal housing portions 30,32 shown in the figures, or variations of those housing portions. FIGS.16A-18F illustrate several example valve flap configuration. The valveflaps 34 shown in FIGS. 16A-C, 17A-C and 18A-C include contoured cutoutsor connection apertures 60 along the bottom end portions 64 of the valveflap 34. The addition of a cutout in the example shown in FIGS. 16A-Bcan provide easier assembly of the backflow prevention assembly,including insertion of the connection protrusions 50 through the valveflap 34 and into the connection recesses 42. FIG. 16C illustrates anexample in which the connection apertures 60 are formed holes at thebottom end portion 64 of the valve flap 34.

The size and shape of the connection apertures 60 can vary as desired toprovide, for example, an interference fit over the connectionprotrusions 50 to ensure tight tolerances. In some arrangements, theconnection apertures 60 can have a size greater than the connectionprotrusions 50 to promote easier assembly and, for example, to ensurefree movement of the valve flap 34 relative to the proximal and distalhousing portions 30, 32. The contoured cutouts and connection apertures60 shown in FIGS. 16A-C can be formed using a variety of techniques suchas, for example, stamping and molding.

FIGS. 16D-E, 17D-E and 18D-E illustrate some example valve flapconfigurations that include a protrusion member 68. The protrusion 68shown in FIG. 16C extends proximally and includes a bottom surface 69that engages a bottom interior floor surface 31 of the proximal portion30 (see FIGS. 19A-D). The protrusion 68 provides a function similar tothe function of the biasing protrusion 38, but is positioned on thevalve flap 34 rather than on the proximal portion 30. The protrusion 68applies a biasing force against the valve flap 34 in a distal directionto bias the valve flap 34 into a closed position shown in FIG. 19A untila sufficient vacuum force is applied to move the valve flap 34 into theopen position shown in FIGS. 19C-D. Typically, the biasing protrusion 38and protrusion 68 of FIG. 16D are not present in the same backflowprevention assembly 14. Either one of the biasing protrusion 38 (and 138described below) and the protrusion 68 can be referred to and functionalas a valve protrusion that helps bias the valve flap 34 into the closedposition.

FIG. 16E illustrates a protrusion 68 having a different constructionthan the protrusion 68 shown in FIG. 16D. The protrusion 68 of FIG. 16Eis configured for use with a biasing protrusion 38 as shown in FIGS.21A-B. The biasing protrusion 38 in FIGS. 21A-B is truncated to providea recess 69 adjacent to the first mating surface 40 and the bottominterior floor surface 31 to receive the protrusion 68. When theprotrusion 68 is positioned in the recess 69, the protrusion 68 is ableto apply a biasing force against the valve flap 34 to hold the valveflap 34 in the closed position shown in FIG. 21A-B.

Many other constructions and combinations of features are possible forthe protrusion 68, proximal portion 14, and biasing protrusion 38 inother arrangements. The protrusion 68 can have any desiredcross-sectional shape, width, and length. In one example, the protrusion68 extends across an entire width of the valve flap 34, while in anotherarrangement the biasing protrusion 68 is a cylindrical shaped memberhaving a rounded distal end.

FIGS. 16F, 17F, 18F illustrate a valve flap 34 that is void ofprotrusions and connection apertures. The valve flap 34 of FIGS. 16F,17F, 18F has a generally circular construction and uniform thickness,although many variations of this construction void of protrusions andconnection apertures are possible.

When assembled, the backflow prevention assembly 14 provides for openingand closing of a fluid flow path through the backflow preventionassembly determined by a position of the valve flap 34 relative to thevalve seats 56. One or both of the biasing protrusion 38 of the proximalhousing portion 30 or the protrusion 68 of the valve flap 34 exerts anaxially directed force upon the valve flap 34 that biases the valve flap34 into the closed position before a threshold vacuum force in theproximal housing portion 30 has been met. When a vacuum pressurecondition exists in the proximal housing portion 30 (e.g., uponapplication of a vacuum force at the flow orifice 46) that exceeds athreshold vacuum pressure condition, the top end portion 62 of the valveflap 34 moves proximally as shown in FIG. 11 to provide an open flowcondition in the backflow prevention assembly 14. When in the openposition, fluid flows along a flow path F1 as shown in FIG. 23 from thetube orifice 52 in the distal housing portion 32 to the tube orifice 52in the proximal housing portion 30. When the vacuum pressure conditionin the proximal housing portion 30 is reduced from the threshold vacuumpressure condition, the valve flap 34 returns to the closed positionshown in FIG. 10 upon the biasing force exerted by the biasingprotrusion 38. When in the closed position shown in FIG. 10, thebackflow prevention assembly 14 substantially prevents backflow ofsubstances positioned in the suction assembly 10 that are locatedproximal of the valve flap 34. An example range of threshold vacuumpressure conditions less than about 15 lb/in² (psi), the atmosphericpressure at sea level. In one example, the threshold pressure conditionis in the range of about 6 to about 12 psi. Another way of measuringvacuum pressure is in inches of Mercury (Hg), wherein all values greaterthan zero inches of Mercury is a vacuum condition (i.e., less thanatmospheric pressure). In one example, the threshold vacuum pressurecondition is in the range of about 1 to about 20 inches of Mercury, andmore preferably about 6 to about 8 inches of Mercury.

The valve flap 34 shown with reference to FIGS. 16B, 17B, 18B includes abending recess 66 that extends across a width of the valve flap 34 at alocation between the top and bottom end portions 62, 64. The valve flap34 is configured to bend about this bending recess 66 and is held inplace between the proximal and distal portions 30, 32 along a bottomportion 64 of the valve flap 34.

FIGS. 22 and 23 illustrate another example valve flap 134 that includesa bending recess 66. The valve flap 134 is engaged by a modified biasingprotrusion 138 that engages the valve flap 134 along the bending recess66 to help hold the valve flap 134 in a retained position betweenproximal and distal portions 130, 132 of the backflow preventionassembly 134 (see FIG. 23). FIG. 23 illustrates the valve flap 134 in abent state within a backflow prevention assembly 114 upon application ofa vacuum pressure in the proximal housing portion 130 that exceeds thethreshold vacuum condition. The valve flap 134 can bend about bendingrecess 66. The valve flap 134 can also bend into a conical or concaveshape about the biasing protrusion 138. The distal housing portion 132can include additional structure such as a retention protrusion 139 thathelps hold the valve flap 134 at a fixed location. The biasingprotrusion 138 and retention protrusion 139 can have shapes and sizesthat promote bending of the valve flap 134 into a conical or concaveshape, or bending about the bending recess 66. The bent shape of thevalve flap 134 can provide an alternate flow path F2 below or around anyother peripheral portion of the valve flap 134. The valve flap 134 canalso provide for reduced noise and other operational advantages in someinstances.

FIGS. 24A-B illustrate another example backflow prevention assembly 214.The backflow prevention assembly 214 proximal and distal portions 230,232, a biasing protrusion 238, a retention protrusion 239, and a valveflap 234. The biasing protrusion 238 includes a contoured shape (e.g., aconvex shape) at its distal end. The retention protrusion 239 includes ashape at its proximal end that mirrors the contoured shape of thebiasing protrusion 238 (e.g., a concave shape). The biasing protrusion238 can also include a connection protrusion 250 that is arranged toengage the valve flap 234 to help retain the valve flap 234 in apredetermined position when the backflow prevention assembly 214 isassembled. The connection protrusion 250 can have a barb-like shape.Alternatively, the connection protrusion 250 can have any desired shapeand size that would be helpful in retaining the valve flap 234 in adesired position.

The contoured shapes of the biasing protrusion 238 and retentionprotrusion 239, as well as the axial position of the engagement point ofthe protrusions 238, 239 with the valve flap 234 relative the valve seat56 tend to bias the valve flap 234 in the closed position.

FIGS. 24C-D illustrate another example backflow prevention assembly 314.The backflow prevention assembly 314 proximal and distal portions 330,332, a biasing protrusion 338, a retention protrusion 339, and a valveflap 334. The biasing protrusion 338 includes a contoured shape (e.g., aconcave shape) at its distal end. The retention protrusion 339 includesa shape at its proximal end that mirrors the contoured shape of thebiasing protrusion 338 (e.g., a convex shape). The mirrored shapes ofthe biasing protrusion 338 and retention protrusion 339 help bias thevalve flap 334 into a closed position.

The axial position of the engagement point of the protrusions 338, 339with the valve flap 234 relative the valve seat 56 tend to bias thevalve flap 234 in the open position away from valve seat 56. Thecontoured shapes of the protrusions 338, 339 tend to bias the valve flap334 into engagement with the valve seat. The axial point of engagementpoint of the protrusions 338, 339 with the valve flap 234 relative thevalve seat 56 can be modified in this and other embodiments (e.g.,assembly 214 discussed above) in combination with various shapes andsizes of the protrusions 338, 339 to vary the performance of valve flap334.

The valve flaps 134, 234, 334 shown in FIGS. 23-24D can be, for example,the valve flap 134 shown in FIG. 22, or any one of the valve flaps 16A-Fdescribed above. Other valve flap configurations are possible for usewith any of the backflow prevention assemblies described above, includevalve flaps that are co-molded or otherwise integrally formed with atleast one of the proximal and distal portions (e.g., portions 30, 32) ofthe backflow prevention assembly.

One advantage related to the valve flaps disclosed with reference toFIGS. 1-24D is that the valve flaps can be manufactured using differentmanufacturing processes, which could offer simpler and less costlymanufacturing process steps for the valve and the overall device. Forexample, the valve flaps shown in FIGS. 16A and 16B can be merelystamped from a sheet of flexible material rather than being molded as anindividual part. The valve flap 34 can also be generated as a separatepiece from each of the housing portions 30, 32. As a result, the valveflap 34 can be made from any desired material using any desired processthat is not limited in any respect to the manufacturing processes andmaterials used for the housing portions 30, 32. Preferably, the valveflap comprises a material such as a Silicone or Thermal PlasticElastomer or other polymeric material. The material selection can bechanged to gain different bending responses from the valve flap fordifferent application of the device, and have an effect on propertiesof, for example, elasticity, stiffness, and moldability. The materialsused for the valve flap can also provide a combination of propertiesthat can influence such performance considerations as acousticvibration.

The ON/OFF valve assembly 16 includes a valve housing 70, a valve member72, a valve actuator 74, a connection boot 76, a connection orifice 78,and a tube connector 80 (see FIG. 4). The valve actuator 74 is exposedon an exterior of the ON/OFF valve assembly 16 so as to be engaged by auser. The valve actuator 74 moves between a closed orientation shown inFIG. 4 wherein the actuator 74 is positioned at a proximal location andan open position wherein the actuator 74 is moved distally of the valvemember 72. Movement of the valve actuator 74 between the proximal anddistal positions moves the valve member 72 between a position in whichfluid flow through the ON/OFF valve assembly 16 is prohibited, and aposition in which the valve member permits fluid flow through the ON/OFFvalve assembly 16.

The connection boot 76 is typically removable from the valve housing 70.In some arrangements, the connection boot 76 comprises a rubber orflexible polymeric material that promotes a fluid tight seal with thevalve housing 70 and the neck portion 36 of the backflow preventionassembly 14. The structure and material properties of the connectionboot 76 also promote relatively easy removal of the connection boot 76from the valve housing 70, and insertion and removal of the backflowprevention assembly 14 from the connecting orifice 76. Alternativeconstructions for the connection boot 76 are shown and described infurther detail below with reference to FIGS. 25-27D.

The tube connection 80 extends from a proximal end of the valve housing70. The tube connector is configured to insert into an open end of thevacuum hose 18. A fluid tight connection is provided between the tubeconnector 80 and the vacuum hose 18. The size of vacuum hose 18 can varyin different applications. For example, the vacuum hose 18 can have aninternal diameter (ID) of about 0.125 inches to about 0.5 inches. Inanother example, the vacuum hose 18 can have an outer diameter (OD) ofabout 0.25 to about 0.75 inches. Smaller diameter sized vacuum hoses canbe referred to as “low volume” vacuum hoses, and larger diameter sizedvacuum hoses can be referred to as “high volume” vacuum hoses in someapplications. The size of the tube connection 80 and other features ofthe assembly 10 can be modified for use with any given size of thevacuum hose 18.

The construction of the ON/OFF valve assembly 16 with the valve member72 positioned generally centrally between the proximal and distal endsof the valve housing 70 makes it possible for there to be suctionedmaterials lingering within the connection boot 76, portions of the valvehousing 70 that are distal of the valve member 72, and ejector tubeassembly 12 that are retained there after the valve member 72 is turnedto an OFF position. Thus, when the ejector tube assembly 12 and/orbackflow prevention assembly 14 is replaced between uses for differentpatients, there is potential for those retained substances to backflowinto the ejector tube assembly 12 and out of the ejector tip 28 beforethe valve member 72 is again opened to suction those substances out ofthe suction assembly 10.

When the assembly 10 is in use drawing substances (e.g., fluid) throughthe assembly under a vacuum pressure applied via the vacuum hose 18, thevacuum pressure can be reduced if the inlet to the ejector tip 28 (seeFIG. 3) is blocked. The ejector tip 28 can be blocked when, for example,the ejector tip 28 engages a sealing surface such as a patient's fleshat the suctioning site or an air impervious material (e.g., plasticsheet). When the ejector tip 28 is blocked, the pressure inside assembly10 is reduced, making it possible for substances in the assembly 10 toflow under gravity forces in the distal direction towards the ejectortip 28. In some limited circumstances, backflow of the substances out ofthe assembly 10 can occur. The use of the backflow prevention assembly14 reduces occurrences of such backflow out of the ejector tip 28.

The cover member 20 includes an outer diameter D3, an extended length L2(see FIG. 8A), an opening restricting member 90, a distal end 92, and aproximal end 94 (see FIGS. 1-4). The cover member 20 is particularlyuseful for covering at least a portion of the ejector tube assembly 12,at least portions of the backflow prevention assembly 14, and at leastportions of the ON/OFF valve assembly 16. In some arrangements, such asthe one shown in FIG. 1, the cover member 20 extends from the ejectortube assembly to cover at least a portion of the vacuum hose 18. Thecover member 20 can be constructed of a material that is collapsibleupon itself such as into the collapsed position shown in FIG. 2, andthen able to re-extend into the extended position shown in FIG. 1.

The opening restricting member 90 can be positioned at the distal end 92as shown in FIGS. 1-4 to help restrict the size of the distal opening ofthe cover member 20. Preferably, the opening restricting member 90 helpsretain the cover member 20 on the ejector tube 22 without permittingproximal retraction over the backflow prevention assembly 14 and/or theON/OFF valve assembly 16. The opening restricting member 90 can alsoprovide a limited opening size that prevents distal advancement of thedistal end of the cover member 20 beyond the ejector tip 28. In otherarrangements, the opening restricting member 90 can be positioned at theproximal end opening of the cover member as shown in FIG. 6. In stillfurther example arrangements, an opening restricting member 90 can bepositioned along the length of the cover member 20 at a location betweenthe proximal and distal ends. In other arrangements, multiple openingrestricting members 90 can be used at various locations along the lengthor at proximal and distal ends of the cover member 20. The openingrestricting member 90 can comprise an elastic material such as, forexample, polyethylene, polyester, latex, or other material such aspolyvinyl chloride. In other arrangements, the restricting member 90 ismerely a reduced diameter portion of the cover member created by, forexample, heat sealing. The opening restricting member 90 can beadjustable in size and shape, or be fixed is size. In one arrangement,the size of the opening restricting member 90 is fixed in size unlesspermanently deformed by application of a radially outward directedforce.

The cover member 20 can comprise a length of tubular structuredmaterial. The tubular structure can be generated using an extrusionprocess, or it can be constructed using a sheet of material that isrolled across its width with side edges sealed together to form the tubeshaped structure. The cover member 20 can include a corrugated structurealong at least a portion of its length that promotes retracting andextending of the cover member 20 as needed along its entire length tocover certain features of the suction assembly 10, or to provideelongation of the cover member 20 at certain features of the suctionassembly 10 such as the ON/OFF valve actuator 74. FIG. 9 illustrates acontinuous roll 98 of cover member material. Predefined lengths of thecover member 20 can be indicated by perforations 95, wherein thedistance between the distal end 92 and the perforation 95 is in therange of the length L2 shown in FIG. 8A. The length L2 can be in therange of about 8 to about 24 centimeters, and more preferably about 16to about 22 centimeters. Another means for collecting a continuouslength of cover member is described below with reference to FIGS. 34-37.

The cover member 20 can include, in addition to or in place of theopening restricting member 90, a length restricting member 96 thatextends along at least a portion of the length L2. FIG. 8B illustrates asingle length restricting member 96 extending from the distal end 92 tothe proximal end 94 of the cover member 20. FIG. 8C illustrates twoseparate lengths restricting members 96A, 96B extending between thedistal and proximal ends 92, 94. In some arrangements, the lengthrestricting member 96 comprises an elastic material such as, forexample, polyethylene, polyester, latex or other plastic materialscommonly used polymeric material. In other examples, the lengthrestricting member 96 functions as a stiffening member that maintains apredefined shape that is applied by the user or corresponds to the shapeof other features of the suction assembly 10. In still furtherarrangements, the length restricting member 96 can be replaced with alength extending member that promotes extension of the cover member 20to its maximum length and resists bunching or restricting of the covermember 20 along its length (e.g., the restricted arrangement shown inFIG. 2).

The length restricting members 96A, 96B can be separate members thatextend along the length L2, or can be a continuous member that extendsaround an entire outer periphery of the cover member 20. In stillfurther arrangements, the members 96A, 96B can replace portions of thecover member 20. The opening restricting member 90 and lengthrestricting members 96 can be secured to the cover member 20 in aseparate manufacturing step, can be co-molded or co-extruded with thecover member 20, or attached in any way desired, for example, an enduser.

In the application of a dental or medical environment, a primaryadvantage of the cover member 20 is to permit the user to operate theON/OFF valve 16 without having to remove their gloves and whilemaintaining sanitary conditions. Currently, users working with a medicalor dental patient wear gloves to promote sanitation. The user oftenoperates the uncovered and possibly contaminated ON/OFF valve withouttaking off their gloves. In some cases some users will go through thetrouble of removing their gloves after touching a contaminated ON/OFFvalve. If the gloves are removed, then it takes time to take them offand put back on a new pair. In some cases, the gloves are wet andsticking and a new pair is required to continue working on the patient.

The Example Connection Boots of FIGS. 25-28D

The connection boot 76 used with the ON/OFF assembly 16 can be modifiedto include a backflow prevention valve for use in addition to or inplace of the backflow prevention assembly 14 described above withreference to FIGS. 1-25. FIG. 27 illustrates an example boot valveassembly 82 shown assembled with an ejector tube assembly 12. The bootvalve assembly 82 includes an adapter 84 and a valve member 86. Theadapter 84 includes a connecting orifice 78, a plurality of barb members48 extending into the connecting orifice 78, and a proximal end surfacethat defines a valve seat 85. (See FIG. 28.) The barbs 48 help retainthe proximal end of the ejector tube 22 within the adapter 84. The valveseat 85 provides a stop surface that defines a distal most axialposition of the valve member 86 when in the closed position. The valvemember 86 extends from an internal sidewall of the connection boot 76.

The examples shown in FIGS. 25-28C include a valve member that isintegral with a sidewall of the connection boot 76. FIGS. 25A, 26A showthe valve member 86 biased in the distal direction before assembly. Whenassembled, the adapter 84 in the example of FIG. 25 and the ejector tubeassembly 12 in the example of FIG. 26 move the valve member 86 into aclosed position, whereby the valve member 86 imposes a biasing force inthe distal direction. This distally directed biasing force prevents thevalve member 86 from moving proximally into an open position until athreshold vacuum pressure condition is exceeded.

Variations of the boot valve assembly 82 shown in FIGS. 25 and 26 areincluded in FIGS. 27A-C and 28A-C. In each of these examples, theconnection boot 76 is configured such that the adapter 84 is not needed.The proximal end of the ejector tube 22 can be secured directly to theconnecting orifice 78 of the connection boot 76. In FIGS. 27A-B, thevalve member 86 is positioned at a proximal end of the connectingorifice 78 so as to be positioned directly adjacent to the proximal mostend of the ejector tube 22 when the ejector tube 22 is inserted in theconnecting orifice 78. FIG. 27C includes a valve member 86 that ispositioned spaced proximal of the connecting orifice 78 so as to befunctionally closer to the valve housing of the ON/OFF valve assembly.

FIGS. 27D, 28D illustrates a further example in which a removable valveassembly 88 is positioned within the connection boot 76. The removablevalve assembly 88 includes first and second portions 87, 89 with thevalve member 86 captured there between. The outer dimensions of theremovable valve assembly 88 match the internal dimensions of theconnection boot 76 thereby helping maintain the removable valve assembly88 in a desired axial position within the connection boot 76. The valveseats and related structure of the removable valve assembly 88 issimilar in some respects to features of the backflow prevention assemblyhousing portions and valve flap described above with reference to FIGS.10-24D.

Any of the arrangements discussed above with reference to the attachedfigures that include an ejector tube can be constructed as a singlepiece object. For example, the combination of the ejector tube assembly12 with the backflow prevention device 14 shown in FIGS. 1-4 can includea combined, single piece construction of the ejector tube assembly 10with the distal housing portion 32 or another portion of the backflowprevention device 14. In another example, the ejector tube assembly 12shown in FIGS. 25 and 26 can be formed as a single piece with theconnection boot 76, adapter 84, or a different distal portion of theON/OFF valve assembly 16.

Additional Cover Member Examples of FIGS. 29-33

The example cover members described herein can be used in combinationwith various features of the suction assembly 10 individually or insubassemblies. For example, the cover member 20 can be used in asubassembly with the ejector tube assembly 12. FIG. 7 illustrates such asubassembly. In the subassembly of FIG. 7, the opening restrictionmember 90 helps retain the cover member 20 along the length of theejector tube 22. The proximal end of the ejector tube 22 can be secureddirectly to the connection boot 76 of the ON/OFF valve assembly 16 asshown in FIG. 29. The cover member 20 can be extended to cover at leasta portion of the ejector tube 22 and substantially all of the ON/OFFvalve assembly 16. Portions of the cover member 20 can also extendproximally beyond the ON/OFF valve assembly 16 to cover at leastportions of the vacuum hose 18.

In another example arrangement, the cover member is provided with asubassembly that includes the ejector tube assembly 12 and the backflowprevention assembly 14 as shown in FIGS. 5 and 6. The proximal end ofthe ejector tube 22 is secured directly to the distal end of thebackflow prevention assembly 14 (see also FIGS. 1-4). In thisarrangement, the opening restrictor member 90 helps retain either thedistal or the proximal end of the cover member 20 along the length ofthe ejector tube 22 between the ejector tube 28 and the backflowprevention assembly 14.

Subassemblies of the cover member with the ejector tube assembly and/orthe backflow prevention assembly can be provided as disposable partsthat are easily replaceable when used with the ON/OFF valve assembly 16.The cover member 20 provides a physical boundary between the user andthe ON/OFF valve assembly 16 and/or the backflow prevention assembly 14,which may have been touched or exposed to unsanitary conditions betweenuses of the suction assembly 10 on different patients. A primary purposeof the cover member 20 is to provide a barrier that will becomecontaminated when used. The cover member 20 captures unsanitizedportions of the suction assembly 10 within the interior of the cover andprovides a sanitary surface on the exterior of the cover. The coverprevents the user of the ON/OFF valve assembly 16 from coming in contactwith the surface of the ON/OFF valve assembly 16, which may becontaminated. The cover member 20 also inhibits transfer of contaminateson the user's hands or gloves to the ON/OFF valve assembly 16 and otherfeatures within the interior of the cover member 20. The cover member 20may become contaminated with fluids, bacteria and other contaminatesassociated with the patient during use of the suction assembly 10. Eachtime the cover member 20 is removed from the suction assembly 10, thosecontaminates that have been transferred to the exterior or interior ofthe cover member 20 are removed with the cover member 20, and thereforeremoved from possible transfer to the next patient by way of the user.

Now referring to FIGS. 30-33, an alternative cover member configurationand retention structure is now described. FIG. 30 illustrates a covermember housing 100 that retains within it a continuous length of covermember 20 that is restricted into a contracted state. The cover memberhousing 100 includes distal and proximal openings 102, 104. The proximalopening 104 is sized to extend the vacuum hose 18 through an interior ofthe cover member housing 100 and into engagement with the tube connector80 of the ON/OFF valve assembly 16. The cover member housing 100includes an internal dimension 108 that can be at least as great as amaximum diameter D3 of the cover member 20. The distal opening 102 isshown in FIGS. 30-33 being about the same as dimension D3 of the covermember 20. In other arrangements, the distal opening 102 can have asmaller size and can be as small as the outer diameter of the vacuumhose 18 plus two times the thickness of the cover member material inorder to permit removal of the cover member 20 from between the vacuumhose 18 and opening 102.

The cover member housing 100 is shown in FIG. 30 positioned completelyproximal of the proximal end of ON/OFF valve assembly 16. In otherarrangements, the cover member housing 100 can be positioned distally soat least a portion of the ON/OFF valve assembly 16 is positionedinternal of the cover member housing 100.

The cover member housing 100 can further include a connector 106 ateither the distal or proximal opening 102, 104. FIG. 33 illustrates theconnector 106 adjacent the proximal opening 104. The connector 106 canbe used to secure the cover member housing 100 to the vacuum hose 18 ata predefined location along the length of the vacuum hose 18. In otherarrangements, the connector 106 can be used to secure the cover memberhousing 100 to other features such as, for example, the ON/OFF valvehousing 70 or other features of the suction assembly 10.

The cover member housing 100 can further include a cutting member (notshown) positioned at, for example, a location adjacent the distalopening 102 to help in cutting off a length of the cover member 20 thathas been drawn distally out from the cover member housing 100. Asmentioned above, the cover member 20 can include perforations 95 atpositions along its length to assist in removing a desired amount of thecover member length that has been drawn distally out of the cover memberhousing 100. In some arrangements, the cover member 20 can include anopening restricting member 90 positioned on at least one of a proximaland distal side of the perforations 95 to provide restriction of one orboth ends of the cover member 20 that has been drawn out of the covermember housing 100.

FIG. 32 illustrates a continuous length of cover member 20 compressedwithin the cover member housing 100. The continuous length of covermember 20 supplied to the housing 100 can be supplied from, for example,the roll 98 of cover member 20 shown in FIG. 9. The cover member housingcan be provided with enough length of cover member 20 for apredetermined number of lengths L2 of cover member. The predeterminednumber of lengths L2 can be, for example, the number needed for acertain number of uses of the suction assembly 10 for a given number ofpatients in a certain time frame. For example, the housing 100 can holdthe number of lengths L2 of cover member 20 for use in a half day, fullday, week, or month's worth of patients being treated. The total lengthof cover member 20 compressed within an particular configuration of thecover member housing 100 can vary depending on, for example, thematerial diameter (D3), whether or not opening restricting members orlength restricting members are used with the cover member 20, and otherconsiderations related to the construction of the cover member 20. Theamount of cover member material held within the cover member housing 100is also dependent upon, for example, the internal dimensions including,for example, the internal diameter and internal length of the covermember housing 100.

In some arrangements, the cover member housing 100 can be permanentlyattached to the vacuum line. The cover member housing can be loaded withrefill cartridges or refill lengths of the cover tubing as desired inany of the above described arrangements. The cover member housing 100can also be constructed as a two piece design that can be disassembledin part to refill the housing and then re-assembled for use.

Additional Backflow Device Examples of FIGS. 34-43

FIGS. 34-36 illustrate another example backflow prevention assembly 414.The backflow prevention assembly 414 includes proximal and distalportions 430, 432, a valve flap 434, and a retention protrusion 439. Theproximal portion 430 includes a pair of connection protrusions 50, 51that extend towards and engage the valve flap 434 when the assembly 414is assembled. The connection protrusions 50, 51 can be shaped with apointed tip that engages the valve flap 434 to help retain the valveflap 434 in a predetermined rotated position. The connection protrusions50, 51 are typically arranged opposite each other (e.g. at 180° rotatedpositions relative to each other). The portions of the valve flap 434that are not engaged by the connection protrusions 50, 51 are movablerelative to the valve seat 56 to create an airflow path from the distalportion 432 to the proximal portion 430.

The distal portion 432 can include a protrusion 439 that engages thevalve flap 434. The protrusion 439 can be arranged extending along aline between the connection protrusions 50, 51. The protrusion 439 canhelp stabilize the valve flap 434 when the valve flap 434 is in an openorientation in which portions of the valve flap 434 move away from thevalve seat 56 to create the fluid flow path between proximal and distalportions 430, 432.

FIG. 37 illustrates another example backflow prevention assembly 514.The backflow prevention assembly 514 includes proximal and distalportions 530, 532, a valve flap 534. The proximal portion 530 includes aconnection protrusion 50 arranged to engage the valve flap 534 when theassembly 514 is assembled. The distal portion 532 includes an arc shapedvalve seat 556. The valve seat 556 is constructed to bias the valve flap534 into a bent orientation relative to the generally planar orientationthat the valve flap 534 typically maintains when in a rest state. Thebent orientation of the valve flap 534 resulting from the arc shape ofthe valve seat 556 tends to create a biasing force within the valve flap534 as the valve flap 534 attempts to return to the planar orientationthat helps maintain contact of the valve flap 534 in a closed stateagainst the valve seat 556. The bend formed in the valve flap 534 by thevalve seat 556 can help return the valve flap 534 into a closedorientation after a vacuum pressure condition that moves the valve flap534 into an open orientation is released.

Portions of the proximal portion 530 can also be formed with an archshape. In one arrangement, the arc shape formed in the proximal portion530 generally mirrors the arc shape of the valve seat 556.

FIG. 38 illustrates another example proximal portion 630 for use withthe backflow prevention assemblies described herein. The proximalportion 630 includes a plurality of connection protrusions 50 positionedalong a mating surface 640. The connection protrusions 50 are arrangedand configured to engage a valve flap of a backflow prevention assembly.A vacuum control air inlet port 641 defined in the proximal portion 630defines an air inlet flow path M. A portion of the vacuum control airinlet port 641 is defined in a distal surface 643 and another portion isdefined in the mating surface 640.

The flow path M provides air flow from external the proximal portion 630to internal the proximal portion 630. The vacuum control air inlet port641 permits air to bypass the valve flap of the backflow preventionassembly until a high enough vacuum pressure condition is generatedwithin the backflow prevention assembly to move the valve flap to anopen orientation. Controlling the shape and size of the vacuum controlair inlet port 641 can help maintain the valve flap in the closedorientation until a specific amount of vacuum pressure is achieved inthe backflow prevention assembly.

FIG. 39 illustrates another example proximal portion 730 for use withthe backflow prevention assemblies described herein. The proximalportion 730 includes vacuum control air inlet ports 741A, 741B that eachdefine an air inlet flow path M. The vacuum control air inlet ports741A, 741B permit air to bypass the valve flap of the backflowprevention assembly similar to the port 641 described above. The vacuumcontrol air inlet ports 741A, 741B are defined in the proximal portion730 at a location proximal of a mating surface 740.

FIGS. 40-41 illustrate another example proximal portion 830 for use withthe backflow prevention assemblies described herein. The proximalportion 830 includes a plurality of engagement ribs 801 positioned alongan outer surface of a neck portion 836. The ribs 801 can improveengagement between the neck portion 836 and a suction device to whichthe proximal portion 830 is mounted. Some example structures of asuction device to which the proximal portion 830 could be mountedinclude a rubber boot and a metal valve housing that includes aninternal O-ring. The structure of a suction device to which the proximalportion 830 is mounted can be susceptible to wear over time that resultsin a loose connection with the proximal portion 830. The engagement ribs801 can be constructed and arranged to provide positive engagementbetween the proximal portion 830 and the mounting structure of thesuction device before and after such wear occurs.

In some embodiments, the engagement ribs 801 can comprise material thatis deformable to permit the ribs 801 to be shaped to whatever size isneeded to maintain positive engagement with the mounting structure ofthe suction device regardless of the amount of wear in the mountingstructure. The engagement ribs 801 can have a generally linear shapethat extends parallel with a longitudinal axis of the proximal portion830. Alternatively, the engagement ribs 801 can include contouredportions and portions that wrap around an exterior of the rib portion836 such as in a helical orientation that is not parallel with thelongitudinal axis of the proximal portion 830. Further, there can be anynumber of engagement ribs 801 provided on the neck portion 836.

FIGS. 42-43 illustrate another example backflow prevention assembly 914.The backflow prevention assembly 914 includes proximal and distalportions 930, 932, and a valve flap 934. The proximal portion 930includes a connection protrusion 50, a biasing protrusion 38, and a keymember 902. The key member 902 includes a tapered surface 904 that isconstructed to help align the key member 902 with a key slot 906 definedin the distal portion 932.

Typically, the backflow prevention assembly 914 is assembled bypositioning the valve flap 934 in a valve seat 56 of the distal portion930. The valve seat can be sized greater than the maximum dimension ofthe valve flap 934 such that the valve flap 934 can be misaligned in thevalve seat 56. Providing the valve seat 56 with a greater size than thevalve flap 934 can make it easier to position the valve flap in thevalve seat. The action of inserting the key member 902 into the key slot906 in the direction S can move the valve flap 934 into properorientation in the direction T (see FIG. 42). The tapered surface 904 ofthe key member 902 can help the key member 902 be inserted into the keyslot 906 with greater ease. The tapered surface 904 can also provide anengagement surface against which an edge of the valve flap 934 engagesafter the key member 902 begins to be inserted into the key slot 906 tohelp move the valve flap 934 in the direction T into a properorientation relative to the proximal and distal portions 930, 932.

The key features 902, 904, 906 can be combined with any other backflowprevention assembly features described herein.

The Example Valve Flap Configurations of FIGS. 44-68

Some valve flap used in the backflow prevention assemblies can includeadditional structure that increases resistance to bending in the valveflap. Resistance to bending is sometimes characterized in terms ofstiffness. Valve flaps with increased stiffness can be less susceptibleto rapid oscillations (e.g., fluttering) in which portions of the valveflap move away from and back into contact with the valve seat.Fluttering can result in an undesirable source of noise when using thebackflow prevention assembly. Fluttering of the valve flap can beparticularly active when the vacuum pressure condition is maintainedwithin a certain range of the threshold pressure condition needed tomove the valve flap into the open state away from the valve seat. Someaspects of the valve flaps described herein, particularly those valveflaps described with reference to FIGS. 44-68 can help reduce noiseproduced by fluttering.

Stiffness typically defined as the resistance of an elastic body todeflection or deformation by an applied force. The stiffness, k, of abody is

k=P/δ

where

P is the applied force

δ is the deflected distance

In the International System of Units, stiffness is typically measured innewtons per meter. The inverse of stiffness is compliance, typicallymeasured in units of meters per newton.

A body may also have a rotational stiffness, k, given by

k=M/θ

where

M is the applied moment

θ is the rotation

In the SI system, rotational stiffness is typically measured innewton-meters per radian.

FIG. 44 illustrates an example valve flap 1034 that includes at leasttwo layers 1012, 1014. The layers 1012, 1014 can be separately formedand secured to each other using a bonding method such as, for example,adhesive bonding or heat bonding. Alternatively, one of the layers 1012,1014 can be formed on the other layer using, for example, usingco-molding processes, vapor deposition, and other methods of applying amaterial layer.

The use of two layers 1012, 1014 can influence bending characteristicsof the valve flap as compared to a valve flap that has only a singlelayer. For example, the use of two layers 1012, 1014 can increasestiffness (i.e., greater resistance to bending) because of, for example,increased total thickness of the valve flap, the addition of bondingmaterial that is used to secure the two layers 1012, 1014 together orthe bond structure itself at the interface of layers 1012, 1014,additional friction that is present at the interface of the layers 1012,1014, or a difference is size, shape, or material composition of one ofthe layers compared to the other layer.

While the layers 1012, 1014 are illustrated as having generally planarsurfaces and uniform thicknesses, various aspects of either of thelayers 1012, 1014 can be altered to change bending properties ofspecific portions of either of layers 1012, 1014 thereby influencingbending properties of the valve flap as a whole.

In some arrangements, the layers 1012, 1014 can be arranged to freelymove relative to each other. Alternatively, the layers 1012, 1014 can besecured at every location in which the layers 1012, 1014 interface. Thelayers 1012, 1014 can also be secured to each other at onlypredetermined locations that are less than the entire mating surfaceswhere the two layers engage.

FIG. 45 illustrates another example valve flap 1134 that includes atleast three layers 1112, 1114, 1116. The use of three or more layers inthe valve flap can influence bending characteristics of the valve flapfor at those reasons discussed above concerning the use of two layers.The use of three or more layers can increase the options for customizingthe bending characteristics of the valve flap because one of the layerscan be provided with any desired feature (e.g., shape, size, materialcomposition) that alone or in combination with features of the otherlayers can influence bending characteristics of the valve flap. Forexample, any one of the layers 1112, 1114, 1116 can have a differentmaterial composition, shape or size as compared to the other layers. Inone example, the middle layer 1116 comprises a material or aconstruction that is more or less stiff than the layers 1112, 1114 ormore or less flexible than the layers 1112, 1114.

Any layer or portion of a layer that influences resistance to bending ofthe valve flap can be considered a stiffening member or stiffeninglayer. The stiffening member can comprise various characteristics suchas, for example, being degradable over cycles of use, chemicallyreactive to change colors or other characteristics over cycles of use,or change temperature, shape or size with cycles of use. Some types ofstiffening members or stiffening layers can reduce resistance to bendingin at least a portion of the valve flap as compared to a valve flap thatdoes not include such a stiffening feature. In the example two-layervalve flap 1034 described above, the mere inclusion of a second layer ofmaterial, even if the second layer is the same shape and size and hasthe same material composition as the other layers and the total valveflap dimensions are the same as a single layer valve flap, the valveflap 1034 can have increased stiffness or less flexibility than thesingle layer valve flap.

In one example, the stiffening member comprises a paper composition thatdecomposes to provide decreased stiffening properties after apredetermined number of uses. In another example, the stiffening layercan include a material that changes color after a certain number ofuses. In such an example, the change in color results from a chemicalreaction could be made to take place at the outlet side of the backflowprevention assembly so that the patient is not exposed to the chemicalreaction. In a further example, the stiffening member can comprise ametallic material, a conductive material, an electroactive polymermaterial (EAP) which when used with other features of the valve flap canperform at least a stiffening function and possible provide otherfunctionality. Such aspects of the stiffening material can be applied toany of the stiffening layers, materials, and valve flap constructionsdescribed herein.

Referring now to FIG. 46, another example valve flap 1234 is shown. Thevalve flap 1234 includes opposing first and second primary surfaces1220, 1222, and a stiffening member 1216 extending from the firstprimary surface 1220. The stiffening member 1216 extends around aperipheral edge of the valve flap 1234. In one arrangement, thestiffening member 1216 extends around an entire peripheral edge orcircumference, whereas in other arrangements the stiffening memberextends only partially around a peripheral edge of the valve flap. Infurther arrangements, the stiffening member covers substantially anentire radially outward facing surface of the valve flap that ispositioned at a periphery of the valve flap.

The stiffening member 1216 can comprise a different material than theremaining portions of the valve flap 1234. Alternatively, the stiffeningmember 1216 can comprise the same material, and can be formedconcurrently with formation of the remaining portions of the valve flap.

The valve flap 1234 can alternatively be described as having a recess1224 defined therein. Portions of the valve flap 1234 can have a greaterthickness than other portions of the valve flap. The increased thicknessportions of the valve flap 1234 provide increased resistance to bendingand other bending-related characteristics for the valve flap 1234, andcan be considered a stiffening feature of the valve flap.

FIG. 47 illustrates a further valve flap configuration 1334 thatcomprises stiffening members 1316A, 1316B that extend in oppositedirections from the first and second primary surfaces 1320, 1322. Thevalve flap 1334 has recesses 1324A, 1324B defined therein. In otherarrangements, such as some of those described below, either one or bothof the recesses 1324A, 1324B can be at least partially filled withanother material such as, for example, a membrane that at leastpartially fills at least one of the recesses 1324 a, 1324B.

The valve flap 1334 can comprise two separate layers wherein each layerhas a construction such as, for example, the construction of valve flap1234 shown in FIG. 46. The two layers can be separately formed and latersecured to each other. Alternatively, the valve flap 1334 can be formedas a single piece.

Some alternative valve flap configurations 1434, 1534, 1634, 1734, 1834,1934 are illustrated with reference to FIGS. 48-53. The valve flap 1434shown in FIG. 48 includes two recesses 1424A, 1424B that are arranged onopposing sides of the valve flap. The recesses 1424A, 1424B have aconcave shape. Many other shapes for recesses 1424A, 1424B andcombinations of shapes are possible. The valve flap 1434 is shown havinga greatest material thickness around the peripheral edge thereof. Inother arrangements, different portions of the valve flap 1434 besidesthe peripheral edge can have the greater thickness.

Valve flap 1534 shown in FIG. 49 includes a stiffening member 1516 thatextends around a peripheral edge thereof. The stiffening member 1516 hasa circular cross-sectional shape that can be described as a bead-typestructure. Alternatively, the stiffening member 1516 can be described astwo arc-shaped structures that extend from opposing primary surfaces ofthe valve flap 1534.

FIG. 50 illustrates a valve flap 1634 that has first and secondstiffening members 1616A, 1616B of different shapes. The stiffeningmember 1616A has a generally rectangular cross-section while thestiffening member 1616B has a generally arc-shaped cross-section.Providing different sized and shaped stiffening member structures onopposite sides or at different locations on a valve flap can influencethe bending properties of a valve flap.

FIG. 51 illustrates a valve flap 1734 that includes an insert stiffeningmember 1730 positioned within a recess 1724 defined in the valve flap1734. The recess 1724 can be defined by a stiffening member 1716 thatextends from a primary surface of the valve flap. The insert 1730 can besized and constructed to at least partially fill the recess 1724. Insome arrangements, the member 1730 can extend out of the recess 1724.

A yet further valve flap configuration 1834 is shown in FIG. 52. Thevalve flap 1834 includes first and second layers 1812, 1814. The firstlayer 1812 includes a stiffening member 1816 extending from a primarysurface 1820. The second layer 1814 can be secured to an opposing sideof the first layer 1812 from the stiffening member 1816. A second layer1814 can possess various characteristics that influence the bendingproperties of the valve flap 1834.

FIG. 53 illustrates a valve flap 1934 that includes first and secondstiffening members 1916A, 1916B. The valve flap 1934 can be formed as anintegral unit. In the illustrated embodiment, the stiffening member1916A, 1916B each have a generally rectangular-shaped construction. Thestiffening members 1916A, 1916B can alternatively be defined as a singlestiffening member having a greater thickness than the remaining portionsof the valve flap 1934. The single stiffening member can define at leastin part a peripheral edge of the valve flap 1934.

FIGS. 54-56 illustrate a valve flap 2034 that includes different shapedand sized stiffening members 2016A, 2016B. The stiffening member 2016Aextends around a periphery of the valve flap 2034 while the stiffeningmembers 2016B are positioned on a primary surface 2020 radially inwardfrom the stiffening member 2016A. The stiffening member 2016A has agenerally rectangular cross-sectional shape as shown in FIGS. 55 and 56.The stiffening member 2016B has a generally arc shaped construction. Thesize, shape and orientation of the stiffening members 2016A-B can bealtered to customize bending characteristics of the valve flap 2034.

FIG. 55 illustrates a valve flap 2034 having a mirror image set ofstiffening members 2016C, 2016D extending from an opposing primarysurface 2022. The stiffening members 2016C, 2016D can have differentshapes and sizes as compared to the stiffening members 2016A, 2016B, andcan be positioned at different locations so as not to be mirror imagesof the stiffening members 2016A, 2016B.

Another valve flap configuration 2134 is shown with reference to FIGS.57-59. The valve flap 2134 includes a first stiffening member 2116Apositioned at a periphery of the valve flap 2134, and a secondstiffening member 2116B that is positioned radially inward from thestiffening member 2116A. The stiffening member 2116 b can comprise aplurality of linear members that intersect each other. An additional setof stiffening members 2116C, 2116D can extend from an opposite primarysurface 2122 from the stiffening members 2116A, 2116B. In somearrangements, the stiffening member 2116B can extend radially outwardinto engagement with the stiffening member 2116A. Various other shapes,sizes, and numbers of stiffening members can be positioned on the valveflap positioned radially inward from the stiffening member 2116A that ispositioned around a periphery of the valve flap 2134.

FIGS. 60-68 illustrate still further valve flap configurations that eachincludes multiple stiffening members. FIGS. 60-62 illustrate a valveflap 2234 that includes a first stiffening member 2216A positionedaround a periphery thereof and a second stiffening member 2216Bpositioned concentric and radially inward from the first stiffeningmember 2116A. Each of the stiffening members 2216A-B has a generallyrectangular cross-sectional area as shown in FIGS. 61 and 62, but canhave different cross-sectional shapes and sizes in other arrangements.

The second stiffening member 2216B extends only partiallycircumferentially. It is possible in other arrangements to provide gapsin the stiffening member so that the stiffening member is notcontinuous.

The valve flap 2234 can include additional stiffening members 2216C and2216D on an opposing side of the valve flap for the stiffening members2216A-B (see FIG. 62). The stiffening members 2216C, 2216D can havedifferent shapes and sizes as well as orientations relative to thestiffening members 2216A-B.

FIGS. 63-65 illustrate a valve flap 2334 that include three concentriccircular shaped stiffening members 2316A-C extending from a firstprimary surface 2320. The stiffening members 2316B-C can have adifferent shape and size than the stiffening member 2316A (see FIG. 64).

The valve flap 2334 can further comprise an additional set of stiffeningmembers 2316D-F positioned on opposing side of the valve flap from thestiffening members 2316A-C.

FIGS. 66-68 illustrate a valve flap 2434 that includes a peripherallyarranged stiffening member 2416A and a plurality of cross stiffeningmembers 2416B. The cross stiffening members 2416 b have a generallylinear shape and extend from one portion of the first stiffening member2416A to another side thereof. The valve flap 2434 can comprise anadditional set of stiffening members 2416 c and 2416 d on an opposingside from the stiffening members 2416A-B.

The stiffening members 2416B are illustrated as being parallel, equallyspaced apart, having the same width, and extending into engagement withthe stiffening member 2416A. In other arrangements, the stiffeningmembers 2416B can have different shapes, sizes, spacings andorientations relative to each other and to the first stiffening member2416A as compared to those illustrated in FIGS. 66-68.

Any of the features of any of the valve flap configurations describedwith reference to FIGS. 44-68 can be combined with or replaced by anyother feature described herein.

Further Backflow Prevention Assemblies of FIGS. 69-79 FIGS. 69-79illustrate some example backflow prevention assemblies that includefeatures that accommodate at least some of the valve flap configurationsdisclosed above with reference to FIGS. 44-68. FIG. 69 illustrates abackflow prevention assembly 1200 that includes proximal and distalportions 1230, 1232 and the valve flap 1234 shown in FIG. 46. Theproximal portion 1230 includes a proximal stiffening member recess 1241.The distal portion 1232 includes a valve seat 56. The proximalstiffening member recess 1241 is sized to receive a portion of thestiffening member 1216 of the valve flap 1234. The recess 1241 can helpretain the valve flap 1234 in a fixed radial and axial position relativeto the proximal and distal portions 1230, 1234.

FIG. 70 illustrates a backflow prevention assembly 1300 that includesproximal and distal portions 1330, 1332 and a valve flap 1934 (see FIG.53). The proximal portion 1330 includes a proximal stiffening memberrecess 1341. The distal portion 1332 defines a valve seat 56 andincludes a distal stiffening member recess 1343. The valve flap 1934includes first and second stiffening members 1916A, 1916 b that extendin opposite directions from opposing primary surfaces of the valve flap1934. The proximal stiffening member recess 1341 is sized to receive aportion of the first stiffening member 1916A. The distal stiffeningmember recess 1343 is sized to receive a portion of the secondstiffening member 1916B. When assembled, the valve flap 1934 is at leastpartially retained within the recesses 1341, 1343 to help retain thevalve flap 1934 in a fixed axial and radial position relative to theproximal and distal portions 1330, 1332.

Another backflow prevention assembly 1400 is illustrated in FIGS. 71-73.The assembly 1400 includes proximal and distal portions 1430, 1432, anda valve flap 1934. The proximal portion 1430 includes at least onebiasing protrusion 1438 that biases the valve flap 1934 into a closedposition at specific locations on one side of the valve flap 1934. Thedistal portion 1432 defines a valve seat 56 and includes a retentionprotrusion 1439. The protrusion 1439 is arranged to engage at least aportion of the valve flap 1934 to support a portion of the valve flapsuch as, for example, along a center line of the valve flap in alignmentwith the biasing protrusions 1438.

A backflow prevention assembly 1500 is described with reference to FIG.74. The assembly 1500 includes proximal and distal portions 1530, 1532and a valve flap 1234. The proximal portion 1530 includes a biasingprotrusion 1538. The distal portion defines a valve seat 56 and includesa retention protrusion 1539. The biasing protrusion 1538 and retentionprotrusion 1539 are sized and shaped to mate with each other with thevalve flap 1234 captured there between. The inner face of theprotrusions 1538, 1539 force the valve flap 1234 into a closedorientation. By moving of the valve flap 1234 in a direction oppositethe open orientation in combination with the use of a stiffening member1216 the incidence of the valve flap unintentionally moving into theopen state to create flutter and other undesirable effects can bereduced.

FIGS. 75-77 illustrate some alternative constructions for biasingprotrusions and proximal stiffening member recesses in the proximalmember of a backflow prevention assembly such as the assembly 1300described above. FIG. 75 illustrates a biasing protrusion 1638 of aproximal portion 1630 that has a generally rectangular cross-section.The proximal stiffening member recess 1641 has a generally rectangularcross-sectional shape and is positioned directly adjacent the protrusion1638.

FIG. 76 illustrates a proximal portion 1730 that includes a biasingprotrusion 1738 having a pointed construction such as a triangularcross-section. A pointed recess 1741 is positioned adjacent to theprotrusion 1738. The recess 41 is defined in part by the shape of theprotrusion 1738.

FIG. 77 illustrates a portion of a proximal portion 1830 that includes abiasing protrusion 1838 and a proximal stiffening member recess 1841.The protrusion 1838 includes a tapered portion with a truncated end.Many other shapes and sizes for the protrusion 1838 are possible.Likewise, the shape, size and relative position of the recess 41compared to the protrusion 1838 is possible in other arrangements.

FIGS. 78-79 illustrate a proximal housing portion 1930 and a distalhousing portion 1932. The proximal portion 1930 includes a proximalstiffening member recess 1941 and a biasing protrusion 1938. The distalportion 1932 includes a distal stiffening member recess 1943, a biasingprotrusion 1939, and sealing edges 1947 a, 1947 b along the valve seat56. The recesses 1941, 1943 have a size and shape that permits somemovement of portions of a valve flap (e.g., stiffening members 1916 a,1916 b as shown in FIG. 79) relative to the housing portions 1930, 1932when the valve flap is in various positions, such as a closed positionagainst the valve seat 56. The shape and size of the recesses 1941, 1943and the protrusions 1916 a, 1916 b can promote contact of the valve flapat one or more sealing edge (e.g., point 1947 b show in FIG. 79) whenthe valve flap is retained between the housing portions 1920, 1932.

Any of the backflow prevention assemblies and in particular the proximalportion thereof can include the features of FIGS. 69-79 and otherfeatures to accommodate various valve flap configurations.

In the foregoing detailed description, various features are occasionallygrouped together in a single embodiment for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments of the subjectmatter require more features than are expressly recited in each claim.Rather, as the following claims reflect, inventive subject matter liesin less than all features of a single disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the detailed description,with each claim standing on its own as a separate preferred embodiment.Therefore, the spirit and scope of the appended claims should not belimited to the description of the preferred versions contained herein.

1. A vacuum backflow prevention system, comprising: a fluid ejector tubeadapted for insertion into a patient's mouth; a backflow preventiondevice, comprising: a distal portion defining a valve seat portion andan inlet, the distal portion operably connected to the fluid ejectortube; a proximal portion defining an outlet, the proximal portionconfigured for operative connection to the distal portion; a valvemember retained between the proximal and distal portions, the valvemember being moveable from a first position substantially blocking fluidflow between the inlet and the outlet, and a second position wherein atleast a portion of the valve member is moved in a direction toward theoutlet to permit fluid to flow from the inlet to the outlet under avacuum condition, the valve member having a stiffening structureextending from a surface of the valve member, the stiffening structureproviding increased resistance to movement of the at least a portion ofthe valve flap from the first position to the second position.
 2. Thesystem of claim 1, wherein the stiffening structure is a second layer ofmaterial positioned on the valve member.
 3. The system of claim 2,wherein the stiffening structure is an embedded layer that is positionedat least partially within the valve member.
 4. The system of claim 1,wherein the stiffening structure extends around a circumference of thevalve member.
 5. The system of claim 1, wherein the valve memberincludes at least first and second stiffening structures.
 6. The systemof claim 1, wherein the stiffening structure has a shape selected fromthe group consisting of hemispherical, linear, and circular.
 7. Thesystem of claim 1, wherein the stiffening structure defines a rimfeature that extends from opposing primary surfaces of the valve member.8. The system of claim 1, wherein at least one of the proximal anddistal portions includes a recessed portion sized to receive a portionof the stiffening structure.
 9. The system of claim 1, wherein thedistal portion includes a valve seat against which a portion of thevalve member engages in the first position to block fluid flow, and astiffening structure recess defined in the valve seat, the stiffeningstructure recess being sized to receive a portion of the stiffeningstructure when the valve member is in the first position.
 10. A backflowprevention device, comprising: a distal portion defining a distalopening; a proximal portion defining a proximal opening; and a valvemember positioned at a location between the distal portion and theproximal portion, the valve member being automatically moveable from afirst position substantially blocking fluid flow between the distalopening and the proximal opening, and a second position wherein aportion of the valve member is moved toward the proximal opening topermit fluid to flow between the distal opening and the proximal openupon application of a predetermined fluid force to the valve member. 11.The device of claim 10, further comprising at least one valve retentionmember positioned between the proximal portion and the distal portion,the at least one valve retention member configured to engage the valvemember to retain the valve member in a predetermined orientationrelative to the proximal portion and the distal portion.
 12. The deviceof claim 11, wherein the at least one valve retention member includes atleast first and second connection protrusions, the first and secondconnection protrusions being arranged to engage the valve member atopposite ends of the valve member.
 13. The device of claim 11, whereinthe at least one valve retention member includes at least first andsecond connection protrusions, the first and second connectionprotrusions being arranged along a centerline of the valve member,wherein the first and second connection protrusions maintain the valvemember in a fixed position along the centerline and two portions of thevalve member on opposing sides of the centerline are movable into thesecond position.
 14. The device of claim 13, wherein the distal portiondefines a support rib that engages a portion of the valve member alongthe centerline.
 15. The device of claim 10, wherein the distal portiondefines a valve seat against which the valve member engages in the firstposition, the valve seat having a contoured shape that provides thevalve member in a pre-bent shape while the valve member is in the firstposition.
 16. The device of claim 10, wherein the proximal portiondefines a vacuum control air inlet port configured to provide air flowinto the device when the valve member is in the first position.
 17. Thedevice of claim 10, wherein the vacuum control air inlet port ispositioned proximal of the valve member.
 18. The device of claim 10,wherein the proximal portion includes a proximal neck portion, the neckportion configured for insertion into a distal open end of a suctiondevice, the neck portion including at least one engagement ribpositioned on an external surface of the neck portion.
 19. The device ofclaim 18, wherein the engagement rib comprises a deformable material.20. The device of claim 11, wherein the at least one valve retentionmember includes a connection protrusion that extends at least partiallythrough a thickness of the valve member.
 21. The device of claim 11,wherein one of the proximal portion and distal portion defines at leastone connection recess, the at least one connection recess configured toreceive the at least one connection protrusion.
 22. The device of claim12, wherein the valve member includes a cut out portion that extendsfrom a periphery of the valve member radially inward to a location inalignment with the at least one connection protrusion.
 23. The device ofclaim 10, wherein the predetermined fluid force is a vacuum forceapplied at the proximal opening.
 24. The device of claim 10, wherein oneof the proximal portion and the distal portion includes an axiallyaligned rib, and the other of the proximal portion and the distalportion including an axially aligned channel sized to receive the ribwhen the proximal and distal portions are connected together.
 25. Thedevice of claim 10, further comprising a key member positioned on one ofthe proximal and distal portions, and a key slot defined in the other ofthe proximal and distal portions, wherein insertion of the key memberinto the key slot orients the valve flap relative to the proximal anddistal portions.
 26. The device of claim 25, wherein the key memberincludes a tapered surface, the tapered surface arranged to engage thevalve flap.
 27. The device of claim 25, wherein the distal memberincludes a valve seat sized greater than a size of the valve flap, thevalve flap being moveable within the valve seat upon engagement by thekey member.